Medicine à la mode

I limped home with my bike, blood seeping through the knee of my jeans. I still have the scar. My flares had got caught up in the chain, and I was sent sprawling from my chopper. Enormous flared collars, cuffs, and trouser bottoms were all the rage then but would be far too dangerous to be allowed on children today for fear of tripping, entanglement, and the real risk of Bri-Nylon static electrocution. But fashion changes, and a few years later I risked sterility by squeezing into drainpipe trousers—such is the power of peer pressure and the media.

Medicine has fashions too, such as in diagnosis. In the 1990s we were flailed repeatedly for underdiagnosing asthma. Reports suggested a lifetime prevalence as high as 30%. So I clad myself in the comfort of the fashionable evidence: every cough was asthma until proved otherwise. Confused and reluctant, patients took my prescription for inhalers. I chose to ignore my inner dissenting voices yelling about overdiagnosis. So when a recent study indicated that we diagnose asthma wrongly in perhaps a third of patients, it is time to question the cut of our medical cloth.

The truth is that data on prevalence are often flawed. They may be based on subjective and leading questionnaires sponsored by special interest groups that use soft diagnostic criteria and thus wittingly or unwittingly ensnare a large segment of the population. Thus we have data indicating a prevalence of attention deficit hyperactivity disorder of 14% and of restless leg syndrome of 8% and that 20 million people in the United Kingdom have a cholesterol concentration requiring treatment—all figures that defy clinical logic. These data are then presented to the public in simplistic disease awareness campaigns that bulldoze through mountains of clinical judgment and experience built up over aeons. The media follow up in stories that focus on the unrepresentative and unsubstantiated experiences of one or two particular sufferers. Doctors are left accused of underdiagnosing many conditions such as depression, dyslexia, autism, dyspraxia, bipolar disorder, hypertension, diabetes, and all the rest.

As a result we duly step up our diagnosis making. Perhaps some of this is justified, but the collateral damage is a society now saturated with sickness. To be well is empowering, but to be inappropriately labelled with an “illness” is a straitjacket that many will never throw off, with consequent long term drug treatment and a restriction in lifestyle and employment opportunities. The dangers of overdiagnosis are more pressing than those of underdiagnosis and are fraying the fabric of society. A fashionable inquiry into the effects of overdiagnosis is long overdue.